If you are using the ALKO sway stabilizer that clamps tightly to the 50 mm ball, be sure you have a way to ensure that the ball cannot rotate, or the nut will become loose. I have installed several of these, and I machine a flat surface on the base of the ball and weld a steel bar across the hitch surface to preclude the ball from rotating.

These hitches work very well, but only with a 50 mm ball. US 2 inch is a bit too big and 1 7/8, while it fits in the hitch, is too loose for the clamp to work.